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Copper core GB cross-linked cable

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Copper core GB cross-linked cable

  • 铜芯国标交联电缆
  • Category: Power cables

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  • Release Date: 2018/08/16
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Detailed introduction
Power cables are cables used to transmit and distribute electrical energy. Power cables are often used in urban underground power grids, power station outlets, internal power supply for industrial and mining enterprises, and under-sea water transmission lines.
In power lines, the proportion of cables is gradually increasing. Power cable is a cable product used to transmit and distribute high-power electrical energy in the trunk line of the power system, including 1-500KV and above various voltage levels and various insulated power cables. [1]

To be classified


Divided by voltage level
According to the voltage level, it can be divided into medium and low voltage power cables (35 kV and below), high voltage cables (110 kV and above), ultra high voltage cables (275 to 800 kV) and ultra high voltage cables (1000 kV and above). In addition, it can be divided into AC cable and DC cable according to the current system.
Divided by insulation material
1. Oil-impregnated paper insulated power cables Power cables with oil-impregnated paper as insulation. Its application history is long. It is safe and reliable, has a long service life, and is inexpensive. The main disadvantage is that the laying is limited by the drop. Since the development of non-drip impregnated paper insulation, the problem of limit drop has been solved, and oil-impregnated paper insulated cables have continued to be widely used.
2. Plastic insulation power cable insulation layer is extruded plastic power cable. Commonly used plastics are polyvinyl chloride, polyethylene, and cross-linked polyethylene. The plastic cable has a simple structure, convenient manufacturing and processing, light weight, convenient installation and installation, and is not restricted by the installation drop. Therefore, it is widely used as medium and low voltage cables, and has a tendency to replace viscous impregnated oil-paper cables. Its big disadvantage is the existence of branching breakdown, which limits its use at higher voltages.
3. The rubber-insulated power cable insulation layer is made of rubber plus various additives, and after being fully mixed, it is extruded and wrapped on a conductive wire core and vulcanized by heating. It is soft and elastic, suitable for occasions with frequent movement and small bending radius.
Common rubber compounds used for insulation are natural rubber-styrene-butadiene rubber mixture, ethylene-propylene rubber, butyl rubber, etc.
Divided by voltage level
1. Low voltage cable: suitable for fixed laying on power transmission and distribution lines with AC 50Hz and rated voltage 3kv and below for power transmission.
2. Medium and low voltage cables: (generally 35KV and below): PVC insulated cables, polyethylene insulated cables, XLPE insulated cables, etc.
3. High-voltage cables: (generally 110KV and above): polyethylene cables and XLPE insulated cables.
4. Extra-high voltage cable: (275 to 800 kV).
5. UHV cables: (1000 kV and above).

basic structure


The basic structure of a power cable consists of a core (conductor), an insulation layer, a shield layer, and a protective layer.

Core

The core is the conductive part of the power cable and is used to transport electrical energy. It is the main part of the power cable.

Insulation

Insulation layer is to electrically isolate the core from the ground and cores of different phases from each other. Electrical energy transmission is an indispensable part of the power cable structure.

Shield

15KV and above power cables generally have conductor shields and insulation shields.

The protective layer

The role of the protective layer is to protect the power cable from the invasion of foreign impurities and moisture, and to prevent external power from directly damaging the power cable.

Industry research


The main advantage

1 occupies less land. It is usually buried in the soil or laid indoors, in trenches and tunnels, the insulation distance between lines is small, no towers are used, it occupies less land, and basically does not occupy space on the ground.
2High reliability. Affected by climatic conditions and surrounding environment, transmission performance is stable and reliability is high.
3 It has more favorable conditions for the development of ultra-high voltage and large capacity, such as low temperature and super-conductive cables.
4 Large distributed capacitance.
5 Low maintenance workload.
6 The possibility of electric shock is small.

research report

"2012 China Power Cable Industry In-Depth Research Report" is the current in-depth market research report on the power cable industry. The report first introduces the background knowledge of power cables, including related concepts, classification, application, industrial chain structure, industry overview of power cables, dynamic analysis of international markets, dynamic analysis of domestic markets, analysis of macroeconomic environment, and economic situation on the power cable industry. Impact, national policy and planning analysis of the power cable industry, technical parameters of power cable products, production process technology, product cost structure, etc .; then statistics were collected on detailed data such as power cable production capacity cost price profit output value profit rate of major Chinese companies, and also statistics of domestic The customers of the 32 power cable products applied the capacity market status, enterprise contact information and other information, and then aggregated statistics and summarized the relevant data of these enterprises to obtain China's power cable capacity market share, production market share, supply demand, supply and demand relationship, and imports. Statistics on the volume of exports, consumption, etc., and also introduces China Power Cable ’s production capacity, sales price, cost, profit, output value, profit margin, etc., and then uses the case model to analyze the risk analysis and investment of new power cable projects Feasibility analysis. Overall, this is an in-depth report specifically for the Chinese power cable industry.

Market space

The continuous and rapid growth of China's economy has provided huge market space for cable products. The strong temptation of the Chinese market has made the world focus on the Chinese market. In the short decades of reform and opening up, China's cable manufacturing industry The huge production capacity formed has made the world look amazing.
In November 2008, in response to the world financial crisis, the government decided to invest 4 trillion yuan to stimulate domestic demand, of which about 40% was used for urban and rural power grid construction and transformation. The national wire and cable industry has a good market opportunity again. Wire and cable companies around the world seize the opportunity to welcome a new round of urban and rural power grid construction and transformation.
The wire and cable industry is the second largest industry in China after the automotive industry, with product variety satisfaction rates and domestic market share exceeding 90%. In the world, China's total output value of wire and cable has surpassed the United States, becoming a major wire and cable producer in the world. With the rapid development of China's wire and cable industry, the number of new enterprises has continued to rise, and the overall technical level of the industry has been greatly improved.
The huge production capacity formed by China's cable manufacturing industry
power cable power cable
Force makes the world look amazing. With the continuous expansion of China's electric power industry, data communication industry, urban rail transportation industry, automobile industry and shipbuilding industries, the demand for wire and cable will also grow rapidly, and the wire and cable industry has huge development potential in the future.

Model Description


Model of power cable
1. Capitalize the Chinese Pinyin letters to indicate the type of insulation, conductor material, inner sheath material and structural characteristics. For example, Z stands for paper (zhi); L stands for aluminum (lv); Q stands for lead (qian); F stands for phase separation (fen); ZR stands for flame retardance (zuran); NH stands for refractory (naihuo).
2. The outer cover is composed of numbers, and has two digits. No number means no armor layer and no outer layer. The first digit indicates the armor and the second digit indicates the outer cover. For example, the outer diameter of the thick steel wire armor fiber is 41.
3. The order of the cable model according to the cable structure is generally: insulation material; conductor material; inner sheath; outer sheath.
4. Cable products are indicated by model, rated voltage and specifications. The method is to add the specified voltage, core number and nominal cross-sectional area after the model.
Model details
(1) Category: H——City communication cable
HP-distribution cable
HJ-office cable
(2) Insulation: Y-polyethylene insulation
YF-foam polyolefin insulation
YP-Foam / Solid Skin Polyolefin Insulation
(3) Inner sheath: A——plastic coated aluminum tape bonded shielding polyethylene sheath
S——Aluminum, steel double-layer metal tape shielded polyethylene sheath
V——Polyvinyl chloride sheath
(4) Features: T-filling with petroleum paste
G-high frequency isolation
C——Self-supporting
(5) Outer sheath: 23——Double-layer anticorrosive steel tape wrapped with polyethylene outer covering
33——Single layer of fine steel wire armored polyethylene quilt
43——Single-layer thick steel wire armored polyethylene quilt
53——Single-layer steel strip wrinkled longitudinally sheathed polyethylene outer covering
553——Double-layer steel strip wrinkled longitudinally sheathed polyethylene outer covering
2) BV copper core PVC insulated wire;
BLV aluminum core PVC insulated wire;
BVV copper core PVC insulated PVC sheathed wire;
BLVV aluminum core PVC insulated PVC sheathed wire;
BVR copper core PVC insulated flexible wire;
RV copper core PVC insulated installation cord;
RVB copper core PVC insulated flat cable
BVS copper core PVC insulated twisted flexible cord;
RVV copper core PVC insulated PVC sheathed flexible wire;
BYR polyethylene insulated flexible wire;
BYVR polyethylene insulated PVC sheathed flexible cord;
RY polyethylene insulated flexible wire;
RYV polyethylene insulated PVC sheathed flexible cord
3) WD: halogen-free low-smoke type
ZR: flame retardant
NH: Refractory
DH: Fireproof

Industry development


Wires and cables have played a very important role in China's infrastructure construction. With the continuous development of China, for the power cable industry, the traditional industry model has been unable to adapt to the development of the currency market for the changing currency market and needs. So for many companies, the transformation of the industry is urgent.
China's wire and cable industry is still a trend of continuous development, but there are also seven major problems, which seriously restrict the healthy and sustainable development of the industry. Take Beijing wire and cable industry as an example.
First, there is a surplus of low- and mid-range products and a shortage of high-end products. There are about tens of thousands of enterprises in China's power cable industry, but most of them are small in scale and their product level is not high, and there are not many companies that can truly win the bid on key national projects. Wires and cables in some special and important areas are often lacking in doors, and only rely on imports when needed.
Second, repeated production and repeated construction are outstanding, and excess production capacity. It should be said that wires and cables are relatively easy to produce products, and the threshold for market access is also low. In the past few years, in the transformation of urban and rural power grids, some companies "seized the opportunity" and rushed to the top; even the power sector was rushing to build factories for production. In recent years, the pace of national capital construction has accelerated, the real estate industry continues to heat up, and many enterprises have risen at the historic moment, seeing what others produce and produce what they produce, causing duplicate products and excess capacity.
Third, local protectionism and monopoly are serious, and the currency market lacks regulation. Due to the overcapacity of wires and cables and fierce competition in the currency market, some local governments enforce local protection and require the use of local products; some power departments only use products produced by companies in this system or related household products, and it is difficult for other companies to enter. Some regulatory agencies also only investigate foreign products, not local and local system products, resulting in unfair competition. In the mid-to-low-end wire and cable currency market where the added value of technology is relatively low, price auctions are quite common. Some workshop companies that do not have the necessary means such as production capacity, quality control, and inspection can be mixed in the industry, becoming the source of counterfeit and shoddy, crude production, cut corners, and replenishing cable products. Means such as price disrupt the competition order of the currency market and intensify disorderly competition in the industry.
Fourth, the price of raw materials keeps rising. Due to the fierce competition in the currency market, it is difficult to raise prices for cable products, and it is difficult for enterprises to survive. The main raw materials of the wire and cable industry are copper and aluminum. Although the prices of copper and aluminum have fluctuated in recent years, they have continued to rise; coupled with the increase in energy, transportation costs and employment wages, the production costs of wire and cable have continued to rise. In order to maintain profitability and maintain production, some companies have to cut corners, reduce product standards, and even produce fake and shoddy products.
Fifth, the investment in research and development is small and the innovation capacity is insufficient. Some cable companies are eager for quick success and are busy developing production and increasing output. They are not willing to invest funds and intelligence to develop new products, especially high-precision products. They also do not attach importance to improving product quality and creating famous brands. As a result, local cable companies lack independent intellectual property rights, key technologies are constrained by people, and high-end technologies and high-end products are developing slowly. According to statistics, only 30% of domestic cable brands have reached the international currency market acceptance and competition level. Enterprises lack professional talents, graduates of related universities are reluctant to work in small and medium-sized cable enterprises, most private employees do not have relevant professional training, there is a serious shortage of technical innovation talents, and most enterprises lack investment in relevant special funds for product development and innovation. All of this has led to insufficient independent technological innovation of current domestic cable manufacturing enterprises, and the product structure has been contradictory.
Sixth, winning the bid at a low price affects the healthy development of the cable industry, and downstream companies occupy a lot of funds from upstream companies. In the bidding activities, downstream customers won the bid with a low price, and cable companies dumped in order to survive low prices, ordering national standard goods for non-standard products. Downstream customers in the industry are strong and large customers, occupying a lot of funds of cable companies, affecting the normal operation of the entire industry.
Seventh, there are many names for cable access qualifications, and cable companies are overwhelmed. Wires and cables are necessary products for various industries, and the requirements for cable performance in different industries are different from each other, and each has its own emphasis. Therefore, various restrictions have been put on the entry of cable products into the network. Spend a lot of manpower, material and financial resources to deal with these various qualifications. For example, ordinary cables need a production license, low-voltage wires must have a 3C compulsory certification, mining cables must have a safety certification for coal mine systems, indoor communication cables must have a network access license from a telecommunications bureau, and television cables must have a network access from a broadcasting department. Permits, LAN cables for computer networks must have a network access license, and flame-retardant and fire-resistant cables must have a record approval certificate from the fire department. What's more, the same product requires licenses from several user departments at the same time. Enterprises are exhausted to obtain various qualifications for network access, and product marketing costs have increased significantly. [1]

Line failure


Common line faults
Short-circuit fault: There are two-phase short-circuit and three-phase short-circuit, which are mostly caused by hidden dangers left in the manufacturing process.
Ground fault: a core or several cores of the cable break down to the ground. Insulation resistance below 10kΩ is called low resistance ground, and above 10kΩ is called high resistance ground. Mainly due to cable corrosion, lead skin cracks, dry insulation, joint technology and materials.
Broken linear fault: one or several cores of the cable are completely or incompletely broken. Cables can be disconnected due to mechanical damage, terrain changes, or short circuits.
Mixed fault: more than two kinds of faults mentioned above.
Causes and Countermeasures of Power Cable Line Failures
External force damage: During the storage, transportation, laying and operation of the cable, it may be damaged by external force, especially the directly buried cable that has been running, and it is vulnerable to damage in the ground construction of other projects. Such accidents often account for 50% of cable accidents. In order to avoid such accidents, in addition to strengthening the quality of work in all aspects of cable storage, transportation, laying, etc., it is more important to strictly implement the ground breaking system.
Protective layer corrosion: Electrochemical corrosion of underground stray current or chemical corrosion of non-neutral soil makes the protective layer invalid and loses its protective effect on insulation. The solution is to install drainage equipment in the stray current-intensive area; when the local soil on the cable line contains chemicals that damage the lead package of the cable, the cable should be installed in the pipe, and the cable should be cushioned with neutral soil And covering, and the cable should be coated with asphalt.
Over-voltage and overload operation: Improper selection of cable voltage, sudden high-voltage ingression during operation, or long-term overload may cause damage to the cable insulation strength and breakdown of the cable. This needs to be solved in time by strengthening inspections and improving operating conditions.
Water immersion in the terminal: due to poor construction, the insulation glue is not filled, resulting in water immersion in the terminal, and eventually exploded. Therefore, it is necessary to strictly implement the construction process regulations and earnestly accept them; strengthen inspections and timely maintenance. The terminal head leaks oil, destroying the sealing structure, making the cable end impregnant dry and dry, increasing the thermal resistance, accelerating the aging of the insulation, easily absorbing moisture, and causing thermal breakdown. When oil leakage is found in the terminal head, inspections should be strengthened, and power failure should be repeated if serious.

Fire and explosion protection


Power plants, substations, and industrial and mining enterprises all use power cables in large quantities. Once the cables explode, they will cause severe fires and power outages. In addition, when the cables burn, a large amount of dense smoke and toxic gases are generated, which not only pollutes the environment, but also endangers human life and safety. For this reason, attention should be paid to the fire prevention of power cables.

Cause of fire

Causes of cable explosion and fire
The insulation layer of power cables is composed of various flammable substances such as paper, oil, hemp, rubber, plastic, asphalt, etc. Therefore, the cables have the possibility of fire and explosion. The cause of the cable fire and explosion is:
(1) Short circuit fault caused by insulation damage. The protective lead of the power cable is damaged during the laying or the cable insulation is mechanically damaged during operation, causing insulation breakdown between the cables or the lead and the resulting arc will cause the insulating material and the outer protective layer of the cable to burn and catch fire.
(2) The cable is overloaded for a long time. For long-term overload operation, the operating temperature of the cable insulation material exceeds the high allowable temperature of normal heating, which makes the insulation of the cable age and dry. This phenomenon of insulation ageing and drying usually occurs on the entire cable line. As the cable insulation ages and dries up, the insulation material loses or reduces the insulation and mechanical properties, so it is easy to burn and burn, or even burn and ignite at multiple locations along the entire length of the cable.
(3) The oil-immersed cable leaks or leaks due to the height difference. When the height difference of the oil-immersed cable is large, the cable may leak oil. As a result of the flow, the upper part of the cable is dried up due to the loss of oil. The thermal resistance of this part of the cable increases, causing the paper insulation to scorch and break down in advance. In addition, due to the downward flow of oil from the upper part, space is created at the upper cable head and negative pressure is generated, which makes the cable easily absorb moisture and make the ends wet. Due to the accumulation of oil in the lower part of the cable, a large static pressure is generated, causing the cable head to leak oil. Moisture and oil leaks from cables increase the chance of a malfunction and fire.
(4) Insulation breakdown of the intermediate joint box. The middle joint of the cable joint box is not tightly crimped, welded poorly, or the joint material is not selected properly. During operation, the joint is oxidized, heated, and glued. When the middle joint of the cable is used, the quality of the insulator poured into the middle joint box does not meet It is required that when filling the insulating agent, there are pores in the box and the cable box has poor sealing, damage and leakage of moisture. All of the above factors can cause insulation breakdown, short circuit, and cable explosion and fire. Electrical Automation Technology Network
(5) The cable head burns. Due to moisture and dirt on the surface of the cable head, the ceramic sleeve of the cable head is broken and the distance between the lead wires is too small, which causes flashover and fire, which causes the surface insulation of the cable head and the lead wire insulation to burn.
(6) Cable fire caused by external fire and heat sources. For example, the spread of fire in oil system, the explosion of fire in oil circuit breaker, spontaneous combustion of coal powder in boiler pulverizing system or coal transportation system, baking of high temperature steam pipes, chemical corrosion of acid and alkali, welding sparks and other fires can make cables A fire has occurred.

How to save

Fire fighting method of cable
Once the cable is on fire, the following methods should be used to extinguish it:
(1) Cut off the power of the fire cable. If the cable catches fire, no matter what causes it, the power should be cut off immediately. Then, according to the path and characteristics of the cable, check it carefully to find out the fault point of the cable. At the same time, personnel should be quickly organized for fire fighting.
(2) The fire in the cable trench cuts off the non-faulty cable power. When the cables in the cable trench catch fire, if the cables laid side by side with the cable trench have obvious fire potential, the power of these cables should be cut off. If the cables are arranged in layers, first cut off the power supply of the heated cable above the fired cable, then cut off the power supply of the cable side by side with the fired cable, and then cut off the power supply of the cable under the fired cable.
(3) Close the cable trench fire door or block both ends of the cable trench. When the cable in the cable trench catches fire, in order to avoid air circulation and facilitate rapid fire extinguishing, the fire isolation door of the cable trench should be closed or both ends should be blocked and suffocated.
(4) Personal protection when extinguishing cable fire. A large amount of dense smoke and poisonous gas will be generated when the cable fires and burns. When extinguishing a cable fire, the rescuer should wear a gas mask. In order to prevent electric shock during the rescue process, rescuers should also wear rubber gloves and insulated boots. If one phase of the high-voltage cable is found to be grounded, rescuers should observe the following: Do not enter within 4m from the fault point in the indoor, and do not enter the fault outdoors. Within 8m of the point, to avoid stepping voltage and contact voltage hurting people. Rescuing injured persons is not limited, but protective measures should be taken.
(5) Fire extinguishing equipment used to extinguish cable fires. Fire extinguishers should be used to extinguish cable fires, such as dry powder fire extinguishers, "1211" fire extinguishers, carbon dioxide fire extinguishers, etc .; it can also be covered with dry sand or loess; if water is used to extinguish the fire, use spray guns; Use other methods to extinguish the fire. After the power is cut off, water can be poured into the cable trench, and the fault is sealed with water to extinguish the fire.
(6) When extinguishing a cable fire, it is forbidden to touch the steel armor of the cable and mobile cables directly with your hands.

Fire prevention measures

Fire prevention measures for cables
To prevent cable fire accidents, the following precautions should be taken:
(1) Use cables that meet thermal stability requirements. The selected cable can meet the long-term rated load heating requirements under normal conditions, and can meet short-term thermal stability under short-circuit conditions to avoid overheating and fire of the cable.
(2) Prevent operation overload. When the cable is running with load, it generally does not exceed the rated load. If the cable is overloaded, the overload time of the cable should be strictly controlled to prevent the cable from catching fire due to overheating.
(3) Observe the relevant regulations for cable laying. Cables should be kept as far away from heat sources as possible, and should not be arranged in parallel or intersecting with steam pipes. If parallel or intersecting, maintain a prescribed distance, and take thermal insulation measures to prevent the entire line of cables from being laid parallel to the top or bottom of heat pipes; in some pipes In the tunnels or trenches, it is generally avoided to lay cables. If you need to lay cables, heat insulation measures should be taken; overhead cables, especially plastic and rubber cables, should have heat insulation measures to prevent heat effects such as hot pipes; when laying cables, The distance between cables, between cables and heat pipes and other pipes, between cables and roads, railways, buildings, etc. shall be in accordance with the regulations; in addition, the cable lay shall have a wavy margin to prevent winter When the cable stops running, it will cause excessive tension and damage the cable insulation. Cable turning should have a small radius of curvature to prevent excessive bending and damage to the cable insulation; joints should be avoided in cable tunnels, because cable joints are where the cables have weak insulation, and cable shorts are prone to occur at the joints. When they must be installed in the tunnel, For intermediate joints, use fire-resistant partitions to isolate them from other cables. The above-mentioned relevant regulations for cable laying have played an effective role in preventing the cable from overheating and insulation damage.
(4) Regular inspections. Power cables should be inspected regularly, and the air temperature and cable temperature in the cable trenches should be measured regularly. In particular, records of the temperature of large-capacity power cables and cable junction boxes should be made. Find and deal with defects in time through inspection.
(5) Close the cable holes and holes tightly and install fire doors and partition walls. In order to prevent cable fire, all cable holes that pass through walls, floors, shafts, cable trenches and enter control rooms, cable mezzanines, control cabinets, instrument cabinets, switch cabinets, etc. must be tightly sealed (closed tightly, flat, beautiful, cables Don't get hurt). For longer cable tunnels and their bifurcations, fire partition walls and fire doors should be provided. Under normal circumstances, the door on the cable trench or hole should be closed. In this way, once the cable catches fire, it can isolate or limit the burning range and prevent the fire from spreading.
(6) Peel the outer jute outer sheath of non-directly buried cables. Directly buried cables have a layer of jute protective layer impregnated with asphalt, which has a protective effect on cables buried directly in the ground. When a directly buried cable enters a cable trench, tunnel, or shaft, its surface should be impregnated with a jute protective layer such as asphalt. Peel to reduce the risk of expanding fire. At the same time, the cover plate above the cable trench should be covered, and the cover plate is complete and solid, and the welding slag is not easy to fall in, reducing the possibility of cable fire.
(7) Keep the cable tunnel clean and properly ventilated. Cable tunnels or trenches should be kept clean and no garbage or debris should be piled up. Water and oil in the tunnels and trenches should be removed in a timely manner. Under normal operating conditions, the cable tunnels and trenches should be properly ventilated.
(8) Keep the cable tunnel or channel well illuminated. The lighting in the cable layer, cable tunnel or trench is often kept in good condition, and special ladders are provided for the tunnels and trench openings that need to be moved up and down to facilitate the operation inspection and the suppression of cable fires.
(9) Prevent fire from entering the cable trench. When performing open flame work near the cable, measures should be taken to prevent the fire from entering the trench.
(10) Regular maintenance and testing. According to the regulations and the actual situation of the cable operation, the cable should be regularly overhauled and tested in order to deal with the defects in time and find the latent fault, the cable runs safely and avoids the occurrence of cable fire. When entering into the cable tunnel or trench for maintenance and test work, the relevant provisions of the "Safety Working Regulations of the Electrical Industry" shall be observed.

Multiple reasons

The outer layer of the power cable is generally a rubber or rubber composite jacket. The role of this layer is insulation, and it also protects the cable from injury.
Power cables are divided into high voltage and low voltage cables. If it is high voltage, there will also be a layer of filler similar to resin, which plays an insulating role. In high voltage cables, this layer is an important part of insulation. There is no such thing in the low voltage, and then there will be something like a ribbon wrapped around it. This is to fix each core of the cable and fill the gap in the middle.
The shielding layer is divided into two cases.The function of the shielding layer of the power cable is twofold: one is because the current passed by the power cable is relatively large, and a magnetic field is generated around the current. In order not to affect other components, adding a shielding layer can change this kind of The electromagnetic field is shielded in the cable. Second, it can play a certain role in ground protection. If the cable core wire is damaged, the leaked current can flow along the shielding layer, such as a ground network, to play a role of safety protection.
Control cables are used in many places, especially for computer system control cables. The shielding layer here is used to shield external influences, because its own current is very weak, and it is very afraid of external electromagnetic fields.
The composition of the power cable should be: conductive wire core, insulation layer, protective layer. Detailed classification (not to mention high voltage and low voltage): conductive wire core, inner semiconducting layer, insulation layer, outer semiconducting layer, copper shield, filler, inner lining layer, double steel belt protective layer, outer protective layer. These parts make up! The above is the description of the 10kV power cable.
Difference from control cable
Power cables are used in power system trunks to transmit and distribute large-function electrical energy, and control cables transmit electrical energy from power distribution points in power systems directly to the power connection lines of various electrical equipment. The rated voltage of power cables is generally 0.6 / 1KV and above, and the control cables are mainly 450 / 750V. In the production of power cables and control cables of the same specifications, the insulation and sheath thickness of the power cables is thicker than that of the control cables.
(1) Control cables belong to electrical equipment cables, and power cables are two of the five categories of cables.
(2) The standard for control cables is 9330 and the standard for power cables is GB12706.
(3) The color of the insulated core of the control cable is generally printed in black and white, and the low voltage of the power cable is generally separated.
(4) The cross section of the control cable generally does not exceed 10 square meters. The power cable is mainly used for transmitting power, and generally has a large cross section.

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Keywords: overhead insulated conductor , overhead conductor , overhead line

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